Field of the Invention
The present invention relates to a substrate transport device used to transport substrates, and to a substrate processing apparatus.
Background Art
US2009/324828 discloses a film forming apparatus and technique in which at least two reactive gases are supplied one after another to a surface of a substrate; the cycle of supplying the reactive gases is executed a number of times; and a multiplicity of layers of a reaction product are thereby laid one on another to form a thin film. In the art disclosed in US2009/324828, a transport arm is used to move wafers.
In a case where a substrate is transported by being put on an arm, care should be taken that the substrate does not move by sliding on the arm. In a case where a substrate is transported while an arm on which the substrate is put is being rotated, however, there is a possibility of the substrate being moved on the arm by centrifugal force acting on the substrate. If the speed of rotation of the arm is increased in order to improve the substrate transport throughput, the possibility of the substrate moving on the arm is increased.
If the arm has a fixed first end and a free second end, a peripheral portion of the arm at the second end is bent downward by the weight thereof. There is a possibility of the substrate sliding easily on the arm due to this bending.